The present invention relates to an insulation displacement contact terminal that is conducted to a core wire of a clad electric wire by being insulation displacement contacted with the clad electric wire.
An insulation displacement contact terminal that is described in Japanese Patent Application Laid-Open Publication No. S57-92762 is constructed of a pair of contact plates, an insulation displacement contact slot between the contact plates, and a folded-back piece.
When press inserting a clad electric wire into the insulation displacement slot, the contact plate is caused to cut into a clothing portion of the clad electric wire and is brought into contact with the core wire inside the clothing portion. By the press insertion of the clad electric wire, the spacing between the contact plates is increased, whereby the core wire is shaved by the contact plate. For this reason, the contact load between the contact plate and the core wire is decreased with the result that the resistance to contact increases. In addition, the clad electric wire becomes likely to be drawn off from between the insulation displacement contact plates. The folded-back piece is engaged with the clad electric wire in order to prevent the draw-off of the clad electric wire.
However, even when having provided the folded-back piece, the increase in resistance to contact that is due to the increase in the spacing between the contact plates cannot be prevented. Also, the structure of the terminal becomes complex by the extent to which the folded-back piece is provided.
The present invention has been made in view of the above and has an object to provide an insulation displacement contact terminal wherein the increase in the spacing between the contact plates is reliably prevented; the increase in the resistance to contact is prevented; the structure is simple; and the draw-off of the electric wire is prevented.
To attain the above object; the insulation displacement contact terminal of the present invention is comprised of a bottom plate, a pair of side plates, a pair of contact plates, and projecting portions. The side plates are respectively extended from both side edges of the bottom plate to oppose each other. The contact plates are respectively partly bent from the side plates to oppose each other. Gaps are formed between the contact plates and the bottom plate. These gaps permit the contact plates to be moved in a direction of their being moved toward each other. The edges of the contact plates that oppose each other define a slot for reception therein of a clad electric wire. The clad electric wire has a core wire and a clothing portion that clothes the core wire. The width of the slot decreases as the movements of the contact plates. As the clad electric wire is press inserted into the slot, the edges are caused to cut into the clothing portion and contact with the core wire. The projecting portions are respectively caused to project from their corresponding contact plates. The projecting portions are located or disposed at the bottom of the slot and are caused to oppose each other. The clad electric wire that has been depressed toward the bottom plate presses the projecting portions and this causes the movements of the contact plates.
In the above construction, by press inserting the clad electric wire into the slot, the edges of the contact plates are caused to cut into the clothing portion of the clad electric wire and are thereby conducted to and contacted with the core wire inside the clothing portion. This provides an insulation displacement contact between the clad electric wire and the terminal.
The clad electric wire that has been press inserted into the slot is brought into contact with the projecting portions at the bottom of the slot to thereby press the projecting portions toward the bottom plate. When the projecting portions are pressed, the contact plates are moved in the direction of their being moved toward each other and as a result the with of the slot is decreased. Therefore, the core wire is reliably contacted with the edges of the contact plates over wide regions thereof, with the result that the resistance to contact between the core wire and the contact plates is decreased. Also, the load of contact with the core wire by the edges is increased and so the clad electric wire is firmly held. Accordingly, by a simple structure of providing the contact plates with the projecting portions, it is possible to prevent the draw-off of the clad electric wire.
The width of the slot may be decreased toward the bottom plate.
In this construction, since the width of the slot is decreased toward the bottom plate, regardless of the size of the outside diameter of the clad electric wire the edges are reliably caused to cut into the clothing portion to thereby contact with the core wire. This provides an insulation displacement contact terminal that can cope with a plurality of kinds of clad electric wires each having a different diameter. Further, because the core wires are converged by the edges, the degree of contact between each core wires is also increased.
Each of the edges of the longitudinal walls may have an introduction portion for introducing the clad electric wire into the slot, and a contact portion that cuts into the clothing portion to thereby contact with the core wire.
In this construction, the introduction portion introduces the clad electric wire into the slot and the contact portion cuts into the clothing portion and is thereby conducted to and contacted with the core wire. Therefore, the clad electric wire and the terminal are easily and smoothly contacted with each other by way of insulation displacement contact.
Each of the plates may have an engagement convex portion that is engaged with the clad electric wire for the purpose of retaining the clad electric wire that has been press inserted into the slot.
In this construction, by the engagement convex portion being engaged with the clad electric wire, this clad electric wire is retained in a state of its having pressed the engagement convex portion. Accordingly, between the contact plates and the core wire, a state of contact becomes stable and this provides an excellently maintained state of conduction.